/*
 * contrib/hstore/hstore.h
 */
#ifndef __HSTORE_H__
#define __HSTORE_H__

#include "fmgr.h"
#include "securec_check.h"
#include "utils/array.h"

/*
 * HEntry: there is one of these for each key _and_ value in an hstore
 *
 * the position offset points to the _end_ so that we can get the length
 * by subtraction from the previous entry.	the ISFIRST flag lets us tell
 * whether there is a previous entry.
 */
typedef struct {
    uint32 entry;
} HEntry;

#define HENTRY_ISFIRST 0x80000000
#define HENTRY_ISNULL 0x40000000
#define HENTRY_POSMASK 0x3FFFFFFF

/* note possible multiple evaluations, also access to prior array element */
#define HSE_ISFIRST(he_) (((he_).entry & HENTRY_ISFIRST) != 0)
#define HSE_ISNULL(he_) (((he_).entry & HENTRY_ISNULL) != 0)
#define HSE_ENDPOS(he_) ((he_).entry & HENTRY_POSMASK)
#define HSE_OFF(he_) (HSE_ISFIRST(he_) ? 0 : HSE_ENDPOS((&(he_))[-1]))
#define HSE_LEN(he_) (HSE_ISFIRST(he_) ? HSE_ENDPOS(he_) : HSE_ENDPOS(he_) - HSE_ENDPOS((&(he_))[-1]))

/*
 * determined by the size of "endpos" (ie HENTRY_POSMASK), though this is a
 * bit academic since currently varlenas (and hence both the input and the
 * whole hstore) have the same limit
 */
#define HSTORE_MAX_KEY_LEN 0x3FFFFFFF
#define HSTORE_MAX_VALUE_LEN 0x3FFFFFFF

typedef struct {
    int32 vl_len_; /* varlena header (do not touch directly!) */
    uint32 size_;  /* flags and number of items in hstore */
                   /* array of HEntry follows */
} HStore;

/*
 * It's not possible to get more than 2^28 items into an hstore, so we reserve
 * the top few bits of the size field.  See hstore_compat.c for one reason
 * why.  Some bits are left for future use here.  MaxAllocSize makes the
 * practical count limit slightly more than 2^28 / 3, or INT_MAX / 24, the
 * limit for an hstore full of 4-byte keys and null values.  Therefore, we
 * don't explicitly check the format-imposed limit.
 */
#define HS_FLAG_NEWVERSION 0x80000000

#define HS_COUNT(hsp_) ((hsp_)->size_ & 0x0FFFFFFF)
#define HS_SETCOUNT(hsp_, c_) ((hsp_)->size_ = (c_) | HS_FLAG_NEWVERSION)

/*
 * "x" comes from an existing HS_COUNT() (as discussed, <= INT_MAX/24) or a
 * Pairs array length (due to MaxAllocSize, <= INT_MAX/40).  "lenstr" is no
 * more than INT_MAX, that extreme case arising in hstore_from_arrays().
 * Therefore, this calculation is limited to about INT_MAX / 5 + INT_MAX.
 */
#define HSHRDSIZE (sizeof(HStore))
#define CALCDATASIZE(x, lenstr) ((x)*2 * sizeof(HEntry) + HSHRDSIZE + (lenstr))

/* note multiple evaluations of x */
#define ARRPTR(x) ((HEntry*)((HStore*)(x) + 1))
#define STRPTR(x) ((char*)(ARRPTR(x) + HS_COUNT((HStore*)(x)) * 2))

/* note multiple/non evaluations */
#define HS_KEY(arr_, str_, i_) ((str_) + HSE_OFF((arr_)[2 * (i_)]))
#define HS_VAL(arr_, str_, i_) ((str_) + HSE_OFF((arr_)[2 * (i_) + 1]))
#define HS_KEYLEN(arr_, i_) (HSE_LEN((arr_)[2 * (i_)]))
#define HS_VALLEN(arr_, i_) (HSE_LEN((arr_)[2 * (i_) + 1]))
#define HS_VALISNULL(arr_, i_) (HSE_ISNULL((arr_)[2 * (i_) + 1]))

/*
 * currently, these following macros are the _only_ places that rely
 * on internal knowledge of HEntry. Everything else should be using
 * the above macros. Exception: the in-place upgrade in hstore_compat.c
 * messes with entries directly.
 */

/*
 * copy one key/value pair (which must be contiguous starting at
 * sptr_) into an under-construction hstore; dent_ is an HEntry*,
 * dbuf_ is the destination's string buffer, dptr_ is the current
 * position in the destination. lots of modification and multiple
 * evaluation here.
 */
#define HS_COPYITEM(dent_, dbuf_, dptr_, dlen_, sptr_, klen_, vlen_, vnull_)                          \
    do {                                                                                              \
        errno_t errorno = EOK;                                                                        \
        errorno = memcpy_s((dptr_), (dlen_), (sptr_), (klen_) + (vlen_));                             \
        securec_check(errorno, "\0", "\0");                                                           \
        (dptr_) += (klen_) + (vlen_);                                                                 \
        (dlen_) = (dlen_) - (klen_) - (vlen_);                                                        \
        (dent_)++->entry = ((dptr_) - (dbuf_) - (vlen_)) & HENTRY_POSMASK;                            \
        (dent_)++->entry = ((((dptr_) - (dbuf_)) & HENTRY_POSMASK) | ((vnull_) ? HENTRY_ISNULL : 0)); \
    } while (0)

/*
 * add one key/item pair, from a Pairs structure, into an
 * under-construction hstore
 */
#define HS_ADDITEM(dent_, dbuf_, dptr_, pair_, len)                                      \
    do {                                                                                 \
        errno_t errorno = EOK;                                                           \
        errorno = memcpy_s((dptr_), len, (pair_).key, (pair_).keylen);                   \
        securec_check(errorno, "\0", "\0");                                              \
        (dptr_) += (pair_).keylen;                                                       \
        (len) = (len) - (pair_).keylen;                                                  \
        (dent_)++->entry = ((dptr_) - (dbuf_)) & HENTRY_POSMASK;                         \
        if ((pair_).isnull)                                                              \
            (dent_)++->entry = ((((dptr_) - (dbuf_)) & HENTRY_POSMASK) | HENTRY_ISNULL); \
        else {                                                                           \
            errorno = memcpy_s((dptr_), len, (pair_).val, (pair_).vallen);               \
            securec_check(errorno, "\0", "\0");                                          \
            (dptr_) += (pair_).vallen;                                                   \
            (len) = (len) - (pair_).vallen;                                              \
            (dent_)++->entry = ((dptr_) - (dbuf_)) & HENTRY_POSMASK;                     \
        }                                                                                \
    } while (0)

/* finalize a newly-constructed hstore */
#define HS_FINALIZE(hsp_, len_, count_, buf_, ptr_)                  \
    do {                                                             \
        int buflen = (ptr_) - (buf_);                                \
        if ((count_))                                                \
            ARRPTR(hsp_)[0].entry |= HENTRY_ISFIRST;                 \
        if ((count_) != HS_COUNT((hsp_))) {                          \
            HS_SETCOUNT((hsp_), (count_));                           \
            errno_t errorno = EOK;                                   \
            errorno = memmove_s(STRPTR(hsp_), len_, (buf_), buflen); \
            securec_check(errorno, "\0", "\0");                      \
        }                                                            \
        SET_VARSIZE((hsp_), CALCDATASIZE((count_), buflen));         \
    } while (0)

/* ensure the varlena size of an existing hstore is correct */
#define HS_FIXSIZE(hsp_, count_)                                          \
    do {                                                                  \
        int bl = (count_) ? HSE_ENDPOS(ARRPTR(hsp_)[2 * (count_)-1]) : 0; \
        SET_VARSIZE((hsp_), CALCDATASIZE((count_), bl));                  \
    } while (0)

/* DatumGetHStoreP includes support for reading old-format hstore values */
extern HStore* hstoreUpgrade(Datum orig);

#define DatumGetHStoreP(d) (d) ? (hstoreUpgrade(d)) : ((HStore*)NULL)

#define PG_GETARG_HS(x) DatumGetHStoreP(PG_GETARG_DATUM(x))

#define NOT_NULL_HS(x)                                                  \
    do {                                                                \
        if (unlikely(x == NULL)) {                                      \
            ereport(ERROR,                                              \
                    (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),           \
                     errmsg("NULL HStore is invalid")));                \
        }                                                               \
    }while(0) 

/*
 * Pairs is a "decompressed" representation of one key/value pair.
 * The two strings are not necessarily null-terminated.
 */
typedef struct {
    char* key;
    char* val;
    size_t keylen;
    size_t vallen;
    bool isnull;   /* value is null? */
    bool needfree; /* need to pfree the value? */
} Pairs;

extern int hstoreUniquePairs(Pairs* a, int4 l, int4* buflen);
extern HStore* hstorePairs(Pairs* pairs, int4 pcount, int4 buflen);

extern size_t hstoreCheckKeyLen(size_t len);
extern size_t hstoreCheckValLen(size_t len);

extern int hstoreFindKey(HStore* hs, int* lowbound, const char* key, uint32 keylen);
extern Pairs* hstoreArrayToPairs(ArrayType* a, int* npairs);

#define HStoreContainsStrategyNumber 7
#define HStoreExistsStrategyNumber 9
#define HStoreExistsAnyStrategyNumber 10
#define HStoreExistsAllStrategyNumber 11
#define HStoreOldContainsStrategyNumber 13 /* backwards compatibility */

/*
 * defining HSTORE_POLLUTE_NAMESPACE=0 will prevent use of old function names;
 * for now, we default to on for the benefit of people restoring old dumps
 */
#ifndef HSTORE_POLLUTE_NAMESPACE
#define HSTORE_POLLUTE_NAMESPACE 1
#endif

#if HSTORE_POLLUTE_NAMESPACE
#define HSTORE_POLLUTE(newname_, oldname_)       \
    PG_FUNCTION_INFO_V1(oldname_);               \
    extern "C" Datum oldname_(PG_FUNCTION_ARGS); \
    extern "C" Datum newname_(PG_FUNCTION_ARGS); \
    Datum oldname_(PG_FUNCTION_ARGS)             \
    {                                            \
        return newname_(fcinfo);                 \
    }                                            \
    extern int no_such_variable
#else
#define HSTORE_POLLUTE(newname_, oldname_) extern int no_such_variable
#endif

#endif /* __HSTORE_H__ */
